The invention relates to equipment for supplying a quantity of hot water, for example for preparing hot drinks, provided with a heating unit for bringing the quantity of water to a predetermined temperature, the inlet of which is connected via an intake pipe and via an intake valve to a cold water pipe and the outlet of which is connected to a discharge pipe, and provided with a control unit which receives a quantity-selection signal from quantity-selection means and supplies control signals to the intake valve and to the heating unit.
Such a device is known in various versions from the prior art.
In the Dutch Patent Application No. 79.04507, such equipment is described in which the measuring means consist of a turbine meter in the intake pipe. Said turbine meter delivers pulses to the control unit via a pulse generator. In the control unit the pulses are counted and the counter reading is compared with a counter reading related to the quantity-selection signal in order to determine when the intake valve has to be closed.
In the Dutch Patent Application No. 81.03534, such equipment is described in which the measuring means are constructed as a clock which measures the time during which the intake valve is opened. Assuming a steady pressure in the cold water pipe, the quantity of incoming cold water will be related to the period of time in which the intake valve is opened.
In the Dutch Patent Specification No. 158,067 such equipment is furthermore described in which the measuring means consist of a measurement reservoir with level probes fitted therein. The level probes supply signals to the control unit which, in response thereto, opens the intake valve on each occasion for the intake of a quantity of water determined by the level difference between the two probes. The control unit is furthermore constructed in a manner such that the intake valve can be opened and closed a number of times, as a result of which a number of charges of water, which are equal on each occasion, can be supplied.
In all these known types of equipment a flow heating system is used for heating the incoming cold water. Because of the use of a flow heating system, the temperature of the hot water supplied will be about 100.degree. C. Although a slight drop in temperature will occur in the preparation of a hot drink with said hot water, for example during the extraction of coffee extract from ground coffee, the resulting coffee extract will nevertheless still have a fairly high temperature between 85.degree. and 90.degree. C. If said coffee is served in plastic cups, the temperature of the coffee in said cups is generally found to be too high. Not only is there the disadvantage in the case of some plastic cups that the cup itself becomes too hot to hold, but also the temperature of the coffee or tea itself proves too high for it to be possible to drink it immediately. Although the temperature usually drops much more considerably if the drinks are served in earthenware cups, even then the problem often occurs that the coffee served is much too hot.